Indicator arrangement

Abstract

An indicator arrangement according to the invention also comprises a resistor (4) the first end of which is connected to between a passive acceleration sensor (1) and a filtering means (2) and the other end is connected to a basic voltage level. An output (5) is also connected to the connection of the first end of the resistor. The indicator arrangement also comprises a direct voltage source (3) the first end of which is connected to a passive acceleration sensor (1) while the other end is connected to a basic voltage level. Voltage can be detected from the output (5) of the indicator arrangement for detecting a fault in the indicator arrangement.

Description

FIELD OF INVENTION[0001]The present invention relates to indicators used in piston-operated internal combustion engines, such as diesel engines or gas engines. The invention especially relates to knock indicators.BACKGROUND ART[0002]Many kinds of different indicators are used in piston engines for observing different units and states in engines. The temperature of a cylinder can be measured, the fuel flow to be supplied can be monitored; the engine running speed can be measured and so on. The knocking occurring in a cylinder of an engine can also be monitored.[0003]A cylinder knocks when the air-fuel mixture introduced therein is ignited in an undesired manner. Typically knocking occurs when the air-fuel mixture or the fuel used separately for ignition is ignited too early. Knocking stresses the engine and can damage the engine. Knock control is used to avoid engine knock by controlling the ignition timing and / or fuel injection for each cylinder. Knock control can reduce the engine ...

AI Technical Summary

Benefits of technology

[0007]The embodiment according to the invention comprises a passive acceleration sensor 1 for forming a voltage signal and filtering means 2 for filtering the said voltage signal. Such an indicator arrangement is for piston engines—usually for detecting knocking in the cylinder of the engine. The indicator arrangement according to the invention also comprises a resistor 4, the first end of which is connected to between the passive acceleration sensor 1 and the filtering means 2 and the other end is connected to the basic voltage level. The connection of the first end of the resistor is also connected to output 5. The indicator arrangement also comprises a direct voltage source 3, the first end of which is connected to a passive acceleration sensor 1 while the second end is connected to the basic voltage level. Voltage can be detected from the output of the indicator arrangement for detecting a fault in the indicator arrangement.

Problems solved by technology

A cylinder knocks when the air-fuel mixture introduced therein is ignited in an undesired manner.

Typically knocking occurs when the air-fuel mixture or the fuel used separately for ignition is ignited too early.

Knocking stresses the engine and can damage the engine.

However, if the sensor or the cables connected thereto are damaged, the signal emitted by the sensor can be incorrect.

The engine can be incorrectly controlled on the basis of the incorrect signal whereby there is a great risk of damaging the engine.

The engine causes vibration that can in the long run damage the sensor, the cables connected thereto or the connections of the cable.

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